First Name:
Jaclyn
Last Name:
Redman
Major Department:
Health and Exercise Science
Thesis Director:
Kevin A. Zwetsloot
Date of Thesis:
Aug 2014
The PI3k/AKT/mTORC1 pathway is a major signaling mechanism that regulates the balance between skeletal muscle protein synthesis and protein degradation, which contributes to the maintenance of muscle mass. Phytoecdysteroids are natural steroid hormones found in certain plant species that possess medicinal and pharmacological properties. Previous studies have demonstrated that the phytoecdysteroid, 20-hydroxyecdysone (20E), stimulates the PI3k/AKT/mTORC1 signaling pathway activation in muscles cells in vitro. This study sought to determine the dose response of 20E for activation of protein synthesis and AKT signaling in response to an acute dose of 20E in skeletal muscle of young mice. Six treatment doses of 20E were used in young male C57BL/6 mice (3-4 months of age). The rate of protein synthesis was measured using the SUnSET technique and AKT signaling was measured via AKT phosphorylation status, both were detected by Western blot analysis. Results revealed that there was a significant treatment effect for puromycin incorporation, but no significant treatment effect existed with AKT phosphorylation between the 20E treatment groups and the Saline group. Although not significant, these results suggest that the 25 mg/kg dose of 20E activates protein synthesis in skeletal muscle of young mice. However, further studies are required to determine if doses lower than 25 mg/kg body weight can be used to stimulate the PI3k/AKT/mTORC1 signaling pathway leading to protein synthesis. Future experiments will use this information to utilize the correct dose of 20E to investigate the optimal influence on mechanisms of protein synthesis in aged skeletal muscle.